Figure 1.

Strategies for combinatorial biosynthesis for the production of siderophore analogs. Modifications performed on gene level (biosynthetic gene cluster) and their impact on siderophore biosynthesis (E1, E2, and E3 represent three enzymes involved in the biosynthesis of a siderophore) are depicted. Substrates, intermediates, and the final product siderophore are represented by circles, triangles and rectangles, and stars, respectively. Colored stars and square represent analogs of the corresponding siderophore or its intermediate, respectively. The red dot represent a single-point mutation performed on the indicated gene and the colored rectangles in e3/E3 modules of a NRPS.